/*
 * Copyright (c) 2009, Hamish Morgan. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the University of Sussex nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
package locusts.server.collisions;

import java.awt.geom.Area;
import java.awt.geom.Rectangle2D;
import javax.vecmath.Vector2d;
import locusts.common.entities.Actor;
import locusts.common.entities.Entity;

/**
 *
 * @author Hamish Morgan
 */
public class ReflectRC implements CollisionResponce {

    public ReflectRC() {
    }

    public void doCollision(Collidable a, Collidable b, double period) {
        Entity A = null;
        if (a instanceof CollidableEntityAdapter) {
            A = ((CollidableEntityAdapter) a).getEntity();
        } else if (a instanceof Entity) {
            A = ((Entity) a);
        } else {
            throw new IllegalArgumentException(
                    "The Collidable arguments to not represent known entities.");
        }
        Entity B = null;
        if (b instanceof CollidableEntityAdapter) {
            B = ((CollidableEntityAdapter) b).getEntity();
        } else if (b instanceof Entity) {
            B = ((Entity) b);
        } else {
            throw new IllegalArgumentException(
                    "The Collidable arguments to not represent known entities.");
        }
        Area intersection = CollisionSystem.getIntersection(a, b);
        Rectangle2D bounds = intersection.getBounds2D();
        double cx = bounds.getCenterX();
        double cy = bounds.getCenterY();

        doCollision(A, B, cx, cy, period);
    }

    public void doCollision(Entity a, Entity b, double cx, double cy,
            double period) {

        // reflection algorithm

        if (a instanceof Actor) {
            Actor A = ((Actor) a);



            final Vector2d normal = new Vector2d(
                    cx - a.getX(),
                    cy - a.getY());
//
//            final Vector2d normal = new Vector2d(
//                    b.getX() - a.getX(),
//                    b.getY() - a.getY());

            final double nn = normal.dot(normal);

            final Vector2d av = new Vector2d(A.getVX(), A.getVY());

            final double vn = normal.dot(av);

            if (vn > 0.0d) {
                final double d = 2d * (vn / nn);

                A.setVelocity(
                        A.getVX() - d * normal.x,
                        A.getVY() - d * normal.y);
            }
            A.setModified();
        }

    }
}
